Most comic artists are familiar with Wally Wood's famous 22 Panels That Always Work. It's a one-page manual explaining how to spice up panels in which people are talking or otherwise doing visually uninteresting things. That, of course, also makes it required learning for comic book writers who need to realize how hard artists have to work to make this stuff readable in a visual medium.
Not confident that writers learned the appropriate lessons from Wood's advice, Mark Waid has partnered with Jeremy Rock to speak directly to members of his profession. Gutters has the entire lesson.